C语言获得把64位数的后32位,32位程序调用64位函数

#pragma warning(push)

#pragma warning(disable : 4409)

DWORD64 __cdecl X64Call(DWORD64 func, int argC, ...)

{

if (!g_isWow64)

return 0;

va_list args;//VA_LIST 是在C语言中解决变参问题的一组宏&＃xff0c;所在头文件&＃xff1a;#include &＃xff0c;用于获取不确定个数的参数。

va_start(args, argC);//VA_START宏&＃xff0c;获取可变参数列表的第一个参数的地址(ap是类型为va_list的指针&＃xff0c;v是可变参数最左边的参数)&＃xff1a;

reg64 _rcx &＃61; { (argC > 0) ? argC--, va_arg(args, DWORD64) : 0 };

reg64 _rdx &＃61; { (argC > 0) ? argC--, va_arg(args, DWORD64) : 0 };//VA_ARG宏&＃xff0c;获取可变参数的当前参数&＃xff0c;返回指定类型并将指针指向下一参数(t参数描述了当前参数的类型)&＃xff1a;

reg64 _r8 &＃61; { (argC > 0) ? argC--, va_arg(args, DWORD64) : 0 };

reg64 _r9 &＃61; { (argC > 0) ? argC--, va_arg(args, DWORD64) : 0 };

reg64 _rax &＃61; { 0 };

reg64 restArgs &＃61; { (DWORD64)&va_arg(args, DWORD64) };//剩余成员用堆栈传递//conversion to QWORD for easier use in inline assembly

reg64 _argC &＃61; { (DWORD64)argC };

DWORD back_esp &＃61; 0;

WORD back_fs &＃61; 0;

__asm

{

;//reset FS segment, to properly handle RFG

mov back_fs, fs

mov eax, 0x2B

mov fs, ax

;//keep original esp in back_esp variable

mov back_esp, esp

;//align esp to 0x10, without aligned stack some syscalls may return errors !

;//(actually, for syscalls it is sufficient to align to 8, but SSE opcodes

;//requires 0x10 alignment), it will be further adjusted according to the

;//number of arguments above 4

;//对齐

and esp, 0xFFFFFFF0

X64_Start();

;//below code is compiled as x86 inline asm, but it is executed as x64 code

;//that&＃39;s why it need sometimes REX_W() macro, right column contains detailed

;//transcription how it will be interpreted by CPU

;//fill first four arguments

REX_W mov ecx, _rcx.dw[0] ;//mov rcx, qword ptr [_rcx]

REX_W mov edx, _rdx.dw[0] ;//mov rdx, qword ptr [_rdx]

push _r8.v ;//push qword ptr [_r8]

X64_Pop(_R8); ;//pop r8

push _r9.v ;//push qword ptr [_r9]

X64_Pop(_R9); ;//pop r9

;// REX_W mov eax, _argC.dw[0] ;//mov rax, qword ptr [_argC]

;// ;//final stack adjustment, according to the ;// ;//number of arguments above 4 ;// test al, 1 ;//test al, 1

jnz _no_adjust ;//jnz _no_adjust

sub esp, 8 ;//sub rsp, 8 对齐对齐对齐&＃xff01;假如有单个参数 需要对齐&＃xff01;&＃xff01;&＃xff01;

_no_adjust: ;// ;// push edi ;//push rdi

REX_W mov edi, restArgs.dw[0] ;//mov rdi, qword ptr [restArgs]

;// ;//put rest of arguments on the stack ;// REX_W test eax, eax ;//test rax, rax

jz _ls_e ;//je _ls_e

REX_W ea edi, dword ptr [edi &＃43; 8*eax - 8] ;//lea rdi, [rdi &＃43; rax*8 - 8]取最后一个的地址

;//_ls: ;// REX_W test eax, eax ;//test rax, rax 判断是否为0

jz _ls_e ;//je _ls_e

push dword ptr [edi] ;//push qword ptr [rdi]

REX_W sub edi, 8 ;//sub rdi, 8

REX_W sub eax, 1 ;//sub rax, 1

jmp _ls ;//jmp _ls

_ls_e: ;// ;// ;//create stack space for spilling registers ;// REX_W sub esp, 0x20 ;//sub rsp, 20h

;// call func ;//call qword ptr [func]

;// ;//cleanup stack ;// REX_W mov ecx, _argC.dw[0] ;//mov rcx, qword ptr [_argC]

REX_W lea esp, dword ptr [esp &＃43; 8*ecx &＃43; 0x20] ;//lea rsp, [rsp &＃43; rcx*8 &＃43; 20h]

;// pop edi ;//pop rdi

;//

//set return value ;// REX_W mov _rax.dw[0], eax ;//mov qword ptr [_rax], rax

X64_End();

mov ax, ds

mov ss, ax

mov esp, back_esp

;//restore FS segment

mov ax, back_fs

mov fs, ax

}

return _rax.v;

}